This invention relates to apparatus which is adapted to break, tear, and crush through plant materials such as branches, cuttings or the like. After passing through the apparatus the plant material is in a condition for disposal, including use of such material as compost.
My U.S. Pat. No. 3,735,933, issued May 29, 1973, discloses an apparatus for the disposal of cuttings or the like which is adapted to break, tear and to crush through such cuttings to prepare the same for composting. The apparatus of this prior patent utilizes a pair of adjacent, generally parallel contra-rotating rotors. Each of the rotors has circumferentially-spaced blades at a rake angle in the direction of rotation, with the blades of one rotor overlapping those of the other rotor during rotation. In U.S. Pat. No. 3,735,933, each rotor includes at least 12 blades disposed at a rake angle of about 20 degrees.
My U.S. Pat. No. 4,923,130, issued May 8, 1990, discloses an apparatus for the disposal of cuttings or the like which is adapted to break, tear and to crush through such cuttings to prepare the same for composting. The apparatus of this prior patent utilizes a pair of adjacent, generally parallel contra-rotating rotors. Each of the rotors has blades tangentially disposed thereon at a rake angle in the direction of rotation, with the blades of one rotor overlapping those of the other rotor during rotation. The blades of this prior patent have flat sides and flat distal end surfaces disposed at substantially 90 degree angles to said sides and interconnected thereto along sharp edges. In U.S. Pat. No. 4,923,130 each rotor includes at least 6 blades disposed at a rake angle of about 23 degrees.
The present invention also relates to apparatus for the disposal of cuttings or the like utilizing a pair of adjacent, generally parallel, contra-rotating rotors to break, tear and to crush through plant material. The apparatus constructed in accordance with the teachings of the present invention, however, incorporates several novel features which contribute to the efficiency and effectiveness of the apparatus as compared with that disclosed in U.S. Pat. Nos. 3,735,933 and 4,923,130.
As given in the previous patents, I had arrived at and used successfully the rotors shown in FIG. 2. However I actually did not know much about how and why they functioned. Recently I have attempted to investigate and analyze my rotors and in particular their blades. I wanted to learn what would happen if I varied a variable. This patent will describe the results of my investigative analysis.
In review, the three important functions of my rotors can be stated as given below:
1. To take hold of, or grasp, the ends of branches which are fed into them;
2. To break, tear, crush through or otherwise produce small piece of wood, rapidly, suitable for composting or other purposes; and
3. To eject these small wood pieces, rapidly, toward a convenient direction. For my present machine this direction is downward, often into boxes.
The operation of my rotors may be further described as being low RPM (revolutions per minute) and high torque. The RPM of the preferred embodiment of the present invention is about 150.
In particular, the present invention includes improved, lower blade-to-rotor ratios which lower the production costs of the rotors while also improving efficiency or effectiveness of the operation of the apparatus. The rotors of the present invention have three, four, five or six blades where the old rotors had 6 blades or more. The angles between adjacent blades of the present invention are 120 degrees for three blade rotors, 90 degrees for four blade rotors, 72 degrees for five blade rotors, and 60 degrees for the improved six blade rotors. Accordingly, the amount of wood material becoming jammed or wedged between adjacent blades is greatly reduced by the present invention embodiment of four and five blade rotors over the prior art.
The improved rotor and blade configuration of the present invention also provides superior function for grasping and feeding plant materials into the apparatus. Prior art rotors contributed to materials fed into the apparatus being thrown upward and out of the apparatus instead of feeding through the rotors.
The improved rotor and blade configuration of the present invention also provides superior crushing through and opening up of the wood fed through them, thus increasing the biomass surface area for improved composting. The new apparatus is particularly adaptable to industrial applications in preparing biomass for further chemical processing, for example to produce ethanol.
Testing indicates the new three, four, five and six blade per rotor configurations increase the crushing effect on plant materials being fed through them to an optimum of six, eight, ten, or twelve times per rotor rotation.
Other features, advantages, and objects of the present invention will become apparent with reference to the following description and accompanying drawings.
These together with other objects of the invention, along with the various features of novelty which characterize the invention, are described with particularity in the claims attached to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the attached drawings and descriptive materials in which there are illustrated preferred embodiments of the invention.